Clinical and biological significance of CXCL12 and CXCR4 expression in adult testes and germ cell tumours of adults and adolescents

Interaction between the chemokine CXCL12 (SDF1) and the G-protein coupled receptor CXCR4 is responsible for the maintenance of adult stem cell niches and is known to play an important role in utero in the migration of primordial germ cells. We demonstrate expression of CXCL12 by Sertoli cells and confirm CXCR4 expression by the germ cell population of the adult human testes. CXCR4 is also known to mediate organ-specific patterns of metastases in a range of common cancers. We identify consistent expression of CXCR4 mRNA and protein in testicular germ cell tumours (TGCT) that accounts for their patterns of relapse in sites of known CXCL12 expression. Extragonadal primary germ cell tumours express CXCR4 and their sites of occurrence are coincident with areas of known CXCL12 expression in utero. We show that CXCL12 stimulates the invasive migration of a TGCT cell line in vitro in a CXCR4-dependent fashion and activates ERK. Furthermore, we demonstrate that expression of CXCL12 in stage I non-seminomas is significantly associated with organ-confined disease post-orchidectomy and reduced risk of relapse (p = 0.003). This may be through the loss of CXCL12 gradients that might otherwise attract cells away from the primary tumour. We propose CXCL12 expression as a potential predictor of subsequent relapse that could lead to avoiding unnecessary treatment and associated late toxicities. Our observations support a role for CXCL12/CXCR4 in the adult germ cell population and demonstrate pathological function in germ cell tumour development and metastasis that may have clinical utility.

KIT and RAS signalling pathways in testicular germ cell tumours: new data and a review of the literature

Testicular germ cell tumours (TGCTs) are the leading cause of cancer deaths in young male Caucasians. Identifying changes in DNA copy number can pinpoint genes involved in tumour development. We defined the smallest overlapping regions of imbalance in TGCTs using array comparative genomic hybridization analysis. Novel regions, or regions which refined those previously reported, were identified. The expression profile of genes from 12p, which is invariably gained in TGCTs, and amplicons defined at 12p11.2-12.1 and 4q12, suggest KRAS and KIT involvement in TGCT and seminoma development, respectively. Amplification of these genes was not found in intratubular germ cell neoplasia adjacent to invasive disease showing these changes, suggesting their involvement in tumour progression. Activating mutations of RAS genes (KRAS or NRAS) and overexpression of KRAS were mutually exclusive events. These, correlations between the expression levels of KIT, KRAS and GRB7 (which encodes an adapter molecule known to interact with the KIT tyrosine kinase receptor) and other reported evidence reviewed here, are consistent with a role for activation of KIT and RAS signalling in TGCT development. In order to assess a role for KIT in seminomas, we modulated the level of KIT expression in TCam-2, a seminoma cell line. The likely seminomatous origin of this cell line was supported by demonstrating KIT and OCT3/4 overexpression and gain of 12p material. Reducing the expression of KIT in TCam-2 through RNA inhibition resulted in decreased cell viability. Further understanding of KIT and RAS signalling in TGCTs may lead to novel therapeutic approaches for these tumours.

A response to Dawson's critical analysis of 'spirituality as "integrative energy"'

Dawson's reply to 'spirituality as integrative energy', particularly his objection to the appropriation of energy as a conceptual descriptor, demonstrates a woefully inaccurate and grossly misleading interpretation of my work. The purpose of this response is to challenge Dawson's assertion that such reformulation effectively strips spirituality of its historical meaning and to provide evidence of its appropriateness. I briefly consider the precepts underlying holism as a moral imperative for professional nursing, the traditional role of spirituality in health and illness, the rise of medical science and its eventual disjunction from metaphysics, and the his torical evolution of nursing. I also comment on the privileged nature of the nurse-client relationship and the social and moral obligation of nurses to engage in holistic practice. Finally, I suggest that the reconceptualization of spirituality as 'integrative energy' represents its dynamic, unifying nature and reassert my contention that 'integrative energy' is an entirely appropriate and eminently suitable definition of spirituality.

'Spirituality as integrative energy': a philosophical analysis as requisite precursor to holistic nursing practice

Spirituality is a universal human phenomenon, yet conceptual confusion, ambiguity and scientific scepticism have prevented adequate investigation into its potential healing effects. A recent resurgence of interest in non-medical sources of healing and holistic medical practices is causing increased speculation regarding the nature of spirituality. The lack of conceptual clarity, and absence of a precise theoretical definition, prevent recognition of spiritual distress and, hence, appropriate nursing intervention. In this paper, current usage and definitions of spirituality are discussed and a philosophical definition of 'spirituality as integrative energy' is proposed. The metaphysical nature of this phenomenon makes it the proper concern of philosophy; consequently, a philosophical analysis of the aforestated proposition was completed using the five predicables of logic theory: species, genus, differentia, logical property and logical accident. Implications of this definition for providing holistic nursing care are also presented.